Revenue (Tables)

12 Months Ended

Dec. 31, 2019

Deferred Revenues Disclosure [Abstract]

Disaggregation of Revenue [Table Text Block]

	Years ended December 31,
	2018		2019
Type of contract
T&M contracts	$	169,416	$	192,153
Fixed-priced contracts		120,291		133,521
Total	$	289,707	$	325,674
Timing of revenue recognition
Products transferred at a point in time	$	6,521	$	8,543
Products and services transferred over time		283,186		317,131
Total	$	289,707	$	325,674

Contract with Customer, Asset and Liability [Table Text Block]

	December 31,
	2018		2019
Trade receivables		38,953		34,615
Contract assets *)		13,846		6,095
Short-term unbilled receivables **)		6,360		9,511
Long-term unbilled receivables **)		-		362
Deferred revenues (short-term contract liabilities)		18,057		21,021
Long-term deferred revenues (long-term contract liabilities) ***)		702		216

***) Included in other long-term liabilities in the consolidated balance sheets

(*) Unbilled receivables relate to revenue recognized in excess of amounts invoiced as the Company has an unconditional right to invoice and receive payment in the future related to its fulfilled obligations.

(**) Contract assets relate to unbilled receivables, which represent revenue recognized on arrangements for which billings have not yet been presented to customers because the amounts were earned but not contractually billable as of the balance sheet date, and the right to consideration is generally subject to milestone completion, client acceptance or factors other than the passage of time.